Table 2.
Characteristics of the five studies included in the meta‐analysis of vitamin D supplementation and cancer mortality from Keum et al. [4]. 25(OH)D, 25‐hydroxyvitamin D; IQR, interquartile range; SD, standard deviation.
| First author, year (reference) | Country | Participants | % Women | Mean age (age range) [years] | Baseline 25(OH)D [nmol·L−1] | Supplementation dose | Duration of intervention [years] | Follow‐up [years] | RR (95% CI) for cancer mortality |
|---|---|---|---|---|---|---|---|---|---|
| Trivedi 2003 [9] | UK | N = 2686; doctors | 31.9 | 74.8 (65–85) | Not measured | 100 000 IU/4 months | 5 | 5 | 0.86 (0.61–1.20) |
| Wactawski‐Wende 2006 [10] | USA | N = 36 282; post‐menopausal women | 100 | 50–79 |
Median (IQR) 42.4 (31.0–58.3) |
400 IU per day | Mean 7 | Mean 7 | 0.89 (0.77–1.03) |
| Avenell 2012 [11] | UK | N = 5292; previous low‐trauma fracture | 84.7 | 77 (≥ 70) |
Mean 38 |
800 IU per day | 2–5 | 3 | 0.85 (0.68–1.06) |
| Scragg 2018 [12] | New Zealand | N = 5110; residents of Auckland | 41.9 | 65.9 (50–84) |
Mean (SD) 66.3 (22.5) |
200 000 IU initial bolus + 100 000 IU per month |
Median (range) 3.3 (2.5–4.2) |
Median 3.3 | 0.99 (0.60–1.64) |
| Manson 2019 [13] | USA |
N = 25 871 71% white, 20.2% black, 4% Hispanic |
50.6 | 67.1 (men ≥ 50, women ≥ 55) |
Median 71 |
2000 IU per day | 3–6 |
Median (range) 5.3 (3.8–6.1) |
0.83 (0.67–1.02) |